Dual completion string gravel pack system and method

ABSTRACT

Gravel packing a wellbore can include simultaneously conveying separate gravel slurry delivery and production strings into the wellbore, flowing a gravel slurry through the gravel slurry delivery string and into an annulus about the production string, and producing fluid from the wellbore via the production string. A gravel packing system can include the gravel slurry delivery and production strings positioned laterally adjacent each other in a wellbore, and the gravel slurry delivery string being in direct fluid communication with one passage in a packer, and the production string being in direct fluid communication with another passage in the packer. Another gravel packing method can include flowing a gravel slurry through a gravel slurry delivery string and into an annulus about a production string, producing fluid from the wellbore via the production string, and these steps being performed without manipulation of either of the strings in the wellbore.

BACKGROUND

This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides a dual completion string gravel pack system and method.

In a typical gravel packing operation, a gravel packing assembly is conveyed into a wellbore on a work string. The work string is used to flow a gravel slurry into the wellbore about the gravel packing assembly, and the work string is manipulated (raised, lowered, rotated, etc.) to set a packer, operate valves, open and close certain flow paths in the gravel packing assembly, etc.

A rig with a drawworks is needed to perform the work string manipulations, and to retrieve the work string and install a production tubing string after the gravel packing operation. However, rig time is very expensive, and so use of the rig during and after a gravel packing operation increases the overall completion and production expenses.

Therefore, it will be appreciated that improvements are needed in the art of gravel packing. These improvements may be useful whether or not a rig is utilized during a gravel packing operation.

SUMMARY

In the disclosure below, systems and methods are provided which bring improvements to the art of gravel packing. One example is described below in which separate tubular strings are used for delivering a gravel slurry, and for producing fluid from a wellbore. Another example is described below in which, once the strings are installed, no manipulation of either of the strings is necessary in order to perform the gravel packing operation.

In one aspect, a method of gravel packing a subterranean wellbore is provided to the art by the disclosure below. The method includes simultaneously conveying a gravel slurry delivery string and a separate production string into the wellbore, flowing a gravel slurry through the gravel slurry delivery string, thereby delivering the gravel slurry into an annulus formed between the production string and the wellbore, and producing fluid from the wellbore via the production string.

In another aspect, a gravel packing system is provided. The system includes a gravel slurry delivery string, a production string positioned laterally adjacent the gravel slurry delivery string in a wellbore, and a packer having passages extending through the packer. The gravel slurry delivery string is in direct fluid communication with one passage, and the production string is in direct fluid communication with another passage.

In yet another aspect, a method of gravel packing a subterranean wellbore includes the steps of: flowing a gravel slurry through a gravel slurry delivery string extending to a surface location, thereby delivering the gravel slurry into an annulus formed between a production string and the wellbore, with the gravel slurry delivery string and the production string being disposed in the same wellbore; producing fluid from the wellbore via the production string; and the gravel slurry flowing and fluid producing steps being performed without manipulation of either of the gravel slurry delivery string or the production string in the wellbore.

These and other features, advantages and benefits will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative examples below and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C are schematic partially cross-sectional views of a gravel packing system and associated method which can embody principles of the present disclosure.

FIG. 2 is a schematic partially cross-sectional view of another configuration of the gravel packing system.

DETAILED DESCRIPTION

The present applicants have determined that it would be beneficial if a gravel packing operation could be performed without requiring the use of a rig to perform work string manipulations. In this manner, the rig could be profitably used at another location while gravel packing operations are performed in the wellbore. However, the principles of this disclosure could be used even if a rig is utilized during the gravel packing operation.

Representatively illustrated in FIGS. 1A-C is a gravel packing system 10 and associated method which embody principles of this disclosure. However, it should be clearly understood that the system 10 and method as depicted in FIGS. 1A-C are merely one example of a wide variety of systems and methods which can incorporate the principles of this disclosure.

For example, in the system 10 as shown in FIGS. 1A-C, a gravel packing assembly 12 is interconnected at a lower end of a generally tubular production string 14, with the gravel packing assembly having well screens 16 positioned in an uncased open hole portion 18 of a generally vertical wellbore 20. However, it is not necessary for the wellbore 20 to be vertical (it could instead be horizontal, deviated or otherwise inclined relative to vertical), and it is not necessary for the screens 16 to be positioned in the open hole portion 18 (the screens could instead be positioned in a cased portion of the wellbore 20). Thus, it will be appreciated that the specific details of the system 10 and method described herein and depicted in the drawings do not limit the principles of this disclosure in any way.

In FIG. 1A, the production string 14 and another generally tubular gravel slurry delivery string 22 are shown after having been simultaneously conveyed into the wellbore 20. Both of the gravel slurry delivery string 22 and the production string 14 extend to a surface location (such as, to a wellhead at a land-based or subsea location, to a rig, etc.).

Above the gravel packing assembly 12, a dual string packer 24 is interconnected to both of the strings, so that the gravel slurry delivery string 22 is in direct communication with one passage 26 extending longitudinally through the packer. The production string 14 is in direct communication with another passage 28 extending longitudinally through the packer.

The passages 26, 28 are laterally spaced apart and isolated from each other in the packer 24. After the packer 24 is set in the wellbore 20, both of the strings 14, 22 are in fluid communication with the wellbore below the packer, but flow between the interior of the production string and an annulus 30 surrounding the production string is filtered by the screens 16.

Once the packer 24 is set, a tubing hanger 32 at or near the surface (e.g., in a wellhead, not shown) is landed and terminated, thereby securing the strings 14, 22 and permitting a rig (not shown) to be moved to another location or slot. Thus, the rig is not needed for manipulation of either of the strings 14, 22 after the tubing hanger 32 is set, and in any subsequent gravel packing and production operations.

As depicted in FIG. 1A, a clear fluid 34 (such as brine) is circulated downward through the production string 14, through a wash pipe 36 in the screens 16, outward through the screens into the annulus 30, and upward through the gravel slurry delivery string 22. The fluid 34 is preferably circulated until it is free of solids when returned to the surface.

In FIG. 1B, the gravel packing operation is performed. A gravel slurry 38 is flowed downwardly through the gravel slurry delivery string 22 and into the annulus 30 surrounding the screens 16. Gravel 40 (see FIG. 1C) is excluded by the screens 16 from flowing into the production string 14, and so the gravel accumulates in the annulus 30, while a fluid portion 42 of the slurry 38 does flow into the screens, into the wash pipe 36, and through the production string 14 to the surface.

In FIG. 1C, the system 10 is depicted after the gravel packing operation, and as the well is placed into production. Formation fluid 44 flows through the gravel 40 in the annulus 30, into the screens 16, into the wash pipe 36, and through the production string 14 to the surface. A plug 46 can be installed in the gravel slurry delivery string 22, if desired, to isolate the string.

Note that the gravel packing operation and subsequent production operation are performed without the necessity of manipulating either of the strings 14, 22. Thus, these operations can be performed without the necessity of a rig to manipulate the strings 14, 22.

Referring additionally now to FIG. 2, another configuration of the gravel packing system 10 is representatively illustrated. The configuration of FIG. 2 is similar in many respects to the configuration of FIGS. 1A-C. However, in the configuration of FIG. 2, multiple swellable packers 48 are used to seal off the annulus 30 between various ones of the screens 16.

By isolating the screens 16 from each other, selective production from multiple zones intersected by the wellbore 20 can be accomplished. For example, it may be desired to permit flow from a zone which is producing hydrocarbon fluid, but prevent or restrict flow from a zone which is producing excessive water or gas.

Flow control devices 50 (such as sliding sleeve valves) are provided along the wash pipe 36 to selectively permit, prevent or choke flow through each of the screens 16. Annular seals 52 are also provided along the wash pipe 36 between the flow control devices 50, so that the flow control devices can individually control flow through each of the screens 16.

The swellable packers 48 include a swellable material 54 which swells when contacted with an appropriate activating agent. When the swellable material 54 swells, the packers 48 will seal against the inner wall of the wellbore 20.

Any type of swellable material may be used for the material 54 in the packers 48. The term “swell” and similar terms (such as “swellable”) are used herein to indicate an increase in volume of a material. Typically, this increase in volume is due to incorporation of molecular components of the fluid into the swellable material itself, but other swelling mechanisms or techniques may be used, if desired. Note that swelling is not the same as expanding, although a material may expand as a result of swelling.

For example, in some conventional packers, a seal element may be expanded radially outward by longitudinally compressing the seal element, or by inflating the seal element. In each of these cases, the seal element is expanded without any increase in volume of the material of which the seal element is made. Thus, in these conventional packers, the seal element expands, but does not swell.

The activating agent which causes swelling of the swellable material 54 could be water and/or hydrocarbon fluid (such as oil or gas). The activating agent could be a gel or a semi-solid material, such as a hydrocarbon-containing wax or paraffin which melts when exposed to increased temperature in a wellbore. In this manner, swelling of the material 54 could be delayed until the material is positioned downhole where a predetermined elevated temperature exists.

The activating agent could cause swelling of the swellable material 54 due to passage of time. The activating agent which causes swelling of the material 54 could be naturally present in the well, or it could be conveyed with the packers 48, conveyed separately or flowed into contact with the material 54 in the well when desired. Any manner of contacting the activating agent with the material 54 may be used in keeping with the principles of the present disclosure.

Various swellable materials are known to those skilled in the art, which materials swell when contacted with water and/or hydrocarbon fluid, so a comprehensive list of these materials will not be presented here. Partial lists of swellable materials may be found in U.S. Pat. Nos. 3,385,367 and 7,059,415, and in U.S. Publication No. 2004-0020662, the entire disclosures of which are incorporated herein by this reference.

As another alternative, the swellable material 54 may have a substantial portion of cavities therein which are compressed or collapsed at the surface condition. Then, after being placed in the well at a higher pressure, the material 54 is expanded by the cavities filling with fluid.

This type of apparatus and method might be used where it is desired to expand the material 54 in the presence of gas rather than oil or water. A suitable swellable material is described in U.S. Publication No. 2007-0257405, the entire disclosure of which is incorporated herein by this reference.

Preferably, the swellable material 54 used in the packers 48 swells by diffusion of hydrocarbons into the swellable material, or in the case of a water swellable material, by the water being absorbed by a super-absorbent material (such as cellulose, clay, etc.) and/or through osmotic activity with a salt like material. Hydrocarbon-, water- and gas-swellable materials may be combined in the packers 48, if desired.

It should, thus, be clearly understood that any type or combination of swellable material which swells when contacted by any type of activating agent may be used in keeping with the principles of this disclosure. Swelling of the material 54 may be initiated at any time, but preferably the material swells at least after the packers 48 are installed in the well.

Swelling of the material 54 may be delayed, if desired. For example, a membrane or coating may be on any or all surfaces of the material 54 to thereby delay swelling of the material. The membrane or coating could have a slower rate of swelling, or a slower rate of diffusion of activating agent through the membrane or coating, in order to delay swelling of the material 54. The membrane or coating could have reduced permeability or could break down in response to exposure to certain amounts of time and/or certain temperatures. Suitable techniques and arrangements for delaying swelling of a swellable material are described in U.S. Pat. No. 7,143,832 and in U.S. Publication No. 2008-0011473, the entire disclosures of which are incorporated herein by this reference.

However, it is not necessary for the packers 48 to include the swellable material 54. Instead, the packers 48 could be conventional compression-set or inflatable packers, if desired.

It may now be fully appreciated that the above disclosure provides several advancements to the art of gravel packing a well. The system 10 described above allows a well to be gravel packed and placed on production, without a rig being needed to manipulate, retrieve or subsequently install work strings and production tubing strings.

In particular, the above disclosure provides a method of gravel packing a subterranean wellbore 20, which method can include the steps of: simultaneously conveying a gravel slurry delivery string 22 and a separate production string 14 into the wellbore 20; flowing a gravel slurry 38 through the gravel slurry delivery string 22, thereby delivering the gravel slurry 38 into an annulus 30 formed between the production string 14 and the wellbore 20; and producing fluid 44 from the wellbore 20 via the production string 14.

Flowing the gravel slurry 38 may include flowing the gravel slurry 38 through a first passage 26 formed through a packer 24, while a fluid portion 42 of the gravel slurry 38 flows through a second passage 28 formed through the packer 24. The first and second passages 26, 28 may be laterally spaced apart from each other in the packer 24.

The simultaneously conveying step may include positioning the gravel slurry delivery string 22 and the production string 14 laterally adjacent each other in the wellbore 20.

The production string 14 may include multiple well screens 16, with a packer 48 being interconnected between at least two of the well screens 16. The packer 48 may include a swellable material 54 which swells in response to contact with an activating agent in the wellbore 20.

The gravel slurry 38 flowing and fluid 44 producing steps can be performed without manipulation of either of the gravel slurry delivery string 22 or the production string 14 in the wellbore 20.

The method can further include supporting the gravel delivery string 22 and the production string 14 with a tubing hanger 32, prior to flowing the gravel slurry 38.

The above disclosure also provides to the art a gravel packing system 10. The system 10 can include a gravel slurry delivery string 22, a production string 14 positioned laterally adjacent the gravel slurry delivery string 22 in a wellbore 20, and a first packer 24 having first and second passages 26, 28 extending through the first packer 24. The gravel slurry delivery string 22 is in direct fluid communication with the first passage 26, and the production string 14 is in direct fluid communication with the second passage 28.

The first and second passages 26, 28 can be laterally spaced apart from each other in the first packer 24.

A gravel slurry 38 preferably flows into the wellbore 20 through the gravel slurry delivery string 22, while a fluid portion 42 of the gravel slurry 38 flows out of the wellbore 20 through the production string 14.

The production string 14 can include multiple well screens 16, with a second packer 48 being interconnected between at least two of the well screens 16. The second packer 48 can include a swellable material 54 which swells in response to contact with an activating agent in the wellbore 20.

The gravel slurry 38 can flow through the gravel slurry delivery string 22 into the wellbore 20 while the gravel slurry delivery string 22 and the production string 14 are supported by a tubing hanger 32.

Another method of gravel packing a subterranean wellbore 20 provided by the above disclosure can include: flowing a gravel slurry 38 through a gravel slurry delivery string 22 extending to a surface location, thereby delivering the gravel slurry 38 into an annulus 30 formed between a production string 14 and the wellbore 20, with the gravel slurry delivery string 22 and the production string 14 being disposed in the same wellbore; producing fluid 44 from the wellbore 20 via the production string 14; and the gravel slurry 38 flowing and fluid 44 producing steps being performed without manipulation of either of the gravel slurry delivery string 22 or the production string 14 in the wellbore 20.

The method can also include simultaneously conveying the gravel slurry delivery string 22 and the separate production string 14 into the wellbore 20. The simultaneously conveying step can include positioning the gravel slurry delivery string 22 and the production string 14 laterally adjacent each other in the wellbore 20.

Flowing the gravel slurry 38 can include flowing the gravel slurry 38 through a first passage 26 formed through a packer 24, while a fluid portion 42 of the gravel slurry 38 flows through a second passage 28 formed through the packer 24. The first and second passages 26, 28 may be laterally spaced apart from each other in the packer 24.

The production string 14 may include multiple well screens 16, with a packer 48 being interconnected between at least two of the well screens 16. The packer 48 can include a swellable material 54 which swells in response to contact with an activating agent in the wellbore 20.

The method can include supporting the gravel delivery string 22 and the production string 14 with a tubing hanger 32, prior to flowing the gravel slurry 38.

It is to be understood that the various examples described above may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present disclosure. The embodiments illustrated in the drawings are depicted and described merely as examples of useful applications of the principles of the disclosure, which are not limited to any specific details of these embodiments.

In the above description of the representative examples of the disclosure, directional terms, such as “above,” “below,” “upper,” “lower,” etc., are used for convenience in referring to the accompanying drawings. In general, “above,” “upper,” “upward” and similar terms refer to a direction toward the earth's surface along a wellbore, and “below,” “lower,” “downward” and similar terms refer to a direction away from the earth's surface along the wellbore.

Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are within the scope of the principles of the present disclosure. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents. 

1. A method of gravel packing a subterranean wellbore, the method comprising: simultaneously conveying a gravel slurry delivery string and a separate production string into the wellbore; flowing a gravel slurry through the gravel slurry delivery string, thereby delivering the gravel slurry into an annulus formed between the production string and the wellbore; and producing fluid from the wellbore via the production string.
 2. The method of claim 1, wherein flowing the gravel slurry further comprises, flowing the gravel slurry through a first passage formed through a packer, while a fluid portion of the gravel slurry flows through a second passage formed through the packer.
 3. The method of claim 2, wherein the first and second passages are laterally spaced apart from each other in the packer.
 4. The method of claim 1, wherein the simultaneously conveying step further comprises positioning the gravel slurry delivery string and the production string laterally adjacent each other in the wellbore.
 5. The method of claim 1, wherein the production string includes multiple well screens, with a packer being interconnected between at least two of the well screens.
 6. The method of claim 5, wherein the packer comprises a swellable material which swells in response to contact with an activating agent in the wellbore.
 7. The method of claim 1, wherein the gravel slurry flowing and fluid producing steps are performed without manipulation of either of the gravel slurry delivery string or the production string in the wellbore.
 8. The method of claim 1, further comprising supporting the gravel delivery string and the production string with a tubing hanger, prior to flowing the gravel slurry.
 9. A gravel packing system, comprising: a gravel slurry delivery string; a production string positioned laterally adjacent the gravel slurry delivery string in a wellbore; and a first packer having first and second passages extending through the first packer, the gravel slurry delivery string being in direct fluid communication with the first passage, and the production string being in direct fluid communication with the second passage.
 10. The system of claim 9, wherein the first and second passages are laterally spaced apart from each other in the first packer.
 11. The system of claim 9, wherein a gravel slurry flows into the wellbore through the gravel slurry delivery string, while a fluid portion of the gravel slurry flows out of the wellbore through the production string.
 12. The system of claim 9, wherein the production string comprises multiple well screens, with a second packer being interconnected between at least two of the well screens, the second packer including a swellable material which swells in response to contact with an activating agent in the wellbore.
 13. The system of claim 9, wherein a gravel slurry flows through the gravel slurry delivery string into the wellbore while the gravel slurry delivery string and the production string are supported by a tubing hanger.
 14. A method of gravel packing a subterranean wellbore, the method comprising: flowing a gravel slurry through a gravel slurry delivery string extending to a surface location, thereby delivering the gravel slurry into an annulus formed between a production string and the wellbore, the gravel slurry delivery string and the production string being disposed in the wellbore; producing fluid from the wellbore via the production string; and the gravel slurry flowing and fluid producing steps being performed without manipulation of either of the gravel slurry delivery string or the production string in the wellbore.
 15. The method of claim 14, further comprising simultaneously conveying the gravel slurry delivery string and the separate production string into the wellbore.
 16. The method of claim 15, wherein the simultaneously conveying step further comprises positioning the gravel slurry delivery string and the production string laterally adjacent each other in the wellbore.
 17. The method of claim 14, wherein flowing the gravel slurry further comprises, flowing the gravel slurry through a first passage formed through a packer, while a fluid portion of the gravel slurry flows through a second passage formed through the packer.
 18. The method of claim 17, wherein the first and second passages are laterally spaced apart from each other in the packer.
 19. The method of claim 14, wherein the production string comprises multiple well screens, with a packer being interconnected between at least two of the well screens, the packer including a swellable material which swells in response to contact with an activating agent in the wellbore.
 20. The method of claim 14, further comprising supporting the gravel delivery string and the production string with a tubing hanger, prior to flowing the gravel slurry. 